The KIPP foundation leads the charter movement with 125 U.S. Schools. Now new charters are joining its quest to close the education gap.

VITALS 34 schools in California; 12,600 studentsSTRATEGY Creating a classroom setting where teachers rotate between clusters of students grouped by common proficiency levels. EXPANSION Aspire has sought to ease tensions between charter enthusiasts and union-backed traditional public schools by taking over failing district schools and their struggling student bodies. But a stifling educational policy climate in California has prompted Aspire to refocus on Memphis, where it will open two K-5 schools in 2013. It plans to serve 19,000 students by 2020. RATE OF ATTRITION* 12%FUNDRAISING In 2010, the Bill and Melinda Gates and Charles and Helen Schwab foundations each promised $8 million to finance more than 4,000 new students.

VITALS 22 schools in the northeast; 7,000 studentsSTRATEGY Every six weeks, teachers and leaders convene for a “data day” to break down students’ assessments by concept (why was a certain passage misunderstood?) and by child (who, specifically, is struggling?). Using the results, students are targeted for small-group instruction, and lesson plans for the next six weeks are tweaked. EXPANSION In 2010, when reading standards in AF’s Brooklyn schools didn’t meet expectations, leaders paused growth to shore up the program. Now they are expanding modestly and plan to have 34 schools in New York, Connecticut, and Rhode Island by 2015. RATE OF ATTRITION 7.4%FUNDRAISING The Carnegie Corporation of New York has given more than $3 million since 2010.

VITALS 28 schools in Texas; 13,000 studentsSTRATEGY Students spend about a quarter
of the day in a digital-learning lab using multi-subject software that slows down for those who are struggling and speeds up for those getting bored. “It yields a ton of performance data we can then react to,” says Idea CEO Tom Torkelson. The lab time lets Idea hire 20% fewer teachers than traditional schools, resulting in a sustainable, scalable business model. EXPANSION Idea plans to have 40,000 students in 56 schools across the Rio Grande Valley by 2017.RATE OF ATTRITION 7.4%FUNDRAISING The Bill and Melinda Gates and Michael and Susan Dell foundations have donated more than $7 million combined since 2007.

VITALS 32 schools in the northeast; 8,000 studentsSTRATEGY Codifying effective teaching skills. “If the word in a kindergarten class’s vocabulary lesson is inquisitive, we’ll film a teacher going through the hundreds of tiny actions that allow students to understand that a person who asks a lot of questions is inquisitive,” says Paul Bambrick-Santoyo, an Uncommon managing director. “Then we edit it into a short training video our teachers can watch.”EXPANSION By 2017, Uncommon plans to have 16,000 students in 45 schools throughout New York, New Jersey, and Massachusetts. RATE OF ATTRITION 10%FUNDRAISING In 2009, billionaire philanthropist Eli Broad gave $1.5 million to be used over three years.

*Rate of attrition is the percentage of students who drop out of a charter school. Attrition is a source of tension among charter-school opponents, as it’s often struggling students who drop out and, should they return to their original noncharter public school, exacerbate the performance gap between the charter and traditional schools. Since school funding is calculated based on student-body size at the beginning of the year, midterm charter-school dropouts that reenroll in their original school also create a budgetary burden. It’s a pickle.